diff options
Diffstat (limited to 'Python/fileutils.c')
| -rw-r--r-- | Python/fileutils.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/Python/fileutils.c b/Python/fileutils.c new file mode 100644 index 0000000000..c563eaa5fb --- /dev/null +++ b/Python/fileutils.c @@ -0,0 +1,431 @@ +#include "Python.h" +#ifdef MS_WINDOWS +# include <windows.h> +#endif + +#ifdef HAVE_STAT + +/* Decode a byte string from the locale encoding with the + surrogateescape error handler (undecodable bytes are decoded as characters + in range U+DC80..U+DCFF). If a byte sequence can be decoded as a surrogate + character, escape the bytes using the surrogateescape error handler instead + of decoding them. + + Use _Py_wchar2char() to encode the character string back to a byte string. + + Return a pointer to a newly allocated wide character string (use + PyMem_Free() to free the memory) and write the number of written wide + characters excluding the null character into *size if size is not NULL, or + NULL on error (conversion or memory allocation error). + + Conversion errors should never happen, unless there is a bug in the C + library. */ +wchar_t* +_Py_char2wchar(const char* arg, size_t *size) +{ + wchar_t *res; +#ifdef HAVE_BROKEN_MBSTOWCS + /* Some platforms have a broken implementation of + * mbstowcs which does not count the characters that + * would result from conversion. Use an upper bound. + */ + size_t argsize = strlen(arg); +#else + size_t argsize = mbstowcs(NULL, arg, 0); +#endif + size_t count; + unsigned char *in; + wchar_t *out; +#ifdef HAVE_MBRTOWC + mbstate_t mbs; +#endif + if (argsize != (size_t)-1) { + res = (wchar_t *)PyMem_Malloc((argsize+1)*sizeof(wchar_t)); + if (!res) + goto oom; + count = mbstowcs(res, arg, argsize+1); + if (count != (size_t)-1) { + wchar_t *tmp; + /* Only use the result if it contains no + surrogate characters. */ + for (tmp = res; *tmp != 0 && + (*tmp < 0xd800 || *tmp > 0xdfff); tmp++) + ; + if (*tmp == 0) { + if (size != NULL) + *size = count; + return res; + } + } + PyMem_Free(res); + } + /* Conversion failed. Fall back to escaping with surrogateescape. */ +#ifdef HAVE_MBRTOWC + /* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */ + + /* Overallocate; as multi-byte characters are in the argument, the + actual output could use less memory. */ + argsize = strlen(arg) + 1; + res = (wchar_t*)PyMem_Malloc(argsize*sizeof(wchar_t)); + if (!res) + goto oom; + in = (unsigned char*)arg; + out = res; + memset(&mbs, 0, sizeof mbs); + while (argsize) { + size_t converted = mbrtowc(out, (char*)in, argsize, &mbs); + if (converted == 0) + /* Reached end of string; null char stored. */ + break; + if (converted == (size_t)-2) { + /* Incomplete character. This should never happen, + since we provide everything that we have - + unless there is a bug in the C library, or I + misunderstood how mbrtowc works. */ + fprintf(stderr, "unexpected mbrtowc result -2\n"); + PyMem_Free(res); + return NULL; + } + if (converted == (size_t)-1) { + /* Conversion error. Escape as UTF-8b, and start over + in the initial shift state. */ + *out++ = 0xdc00 + *in++; + argsize--; + memset(&mbs, 0, sizeof mbs); + continue; + } + if (*out >= 0xd800 && *out <= 0xdfff) { + /* Surrogate character. Escape the original + byte sequence with surrogateescape. */ + argsize -= converted; + while (converted--) + *out++ = 0xdc00 + *in++; + continue; + } + /* successfully converted some bytes */ + in += converted; + argsize -= converted; + out++; + } +#else + /* Cannot use C locale for escaping; manually escape as if charset + is ASCII (i.e. escape all bytes > 128. This will still roundtrip + correctly in the locale's charset, which must be an ASCII superset. */ + res = PyMem_Malloc((strlen(arg)+1)*sizeof(wchar_t)); + if (!res) goto oom; + in = (unsigned char*)arg; + out = res; + while(*in) + if(*in < 128) + *out++ = *in++; + else + *out++ = 0xdc00 + *in++; + *out = 0; +#endif + if (size != NULL) + *size = out - res; + return res; +oom: + fprintf(stderr, "out of memory\n"); + return NULL; +} + +/* Encode a (wide) character string to the locale encoding with the + surrogateescape error handler (characters in range U+DC80..U+DCFF are + converted to bytes 0x80..0xFF). + + This function is the reverse of _Py_char2wchar(). + + Return a pointer to a newly allocated byte string (use PyMem_Free() to free + the memory), or NULL on conversion or memory allocation error. + + If error_pos is not NULL: *error_pos is the index of the invalid character + on conversion error, or (size_t)-1 otherwise. */ +char* +_Py_wchar2char(const wchar_t *text, size_t *error_pos) +{ + const size_t len = wcslen(text); + char *result = NULL, *bytes = NULL; + size_t i, size, converted; + wchar_t c, buf[2]; + + if (error_pos != NULL) + *error_pos = (size_t)-1; + + /* The function works in two steps: + 1. compute the length of the output buffer in bytes (size) + 2. outputs the bytes */ + size = 0; + buf[1] = 0; + while (1) { + for (i=0; i < len; i++) { + c = text[i]; + if (c >= 0xdc80 && c <= 0xdcff) { + /* UTF-8b surrogate */ + if (bytes != NULL) { + *bytes++ = c - 0xdc00; + size--; + } + else + size++; + continue; + } + else { + buf[0] = c; + if (bytes != NULL) + converted = wcstombs(bytes, buf, size); + else + converted = wcstombs(NULL, buf, 0); + if (converted == (size_t)-1) { + if (result != NULL) + PyMem_Free(result); + if (error_pos != NULL) + *error_pos = i; + return NULL; + } + if (bytes != NULL) { + bytes += converted; + size -= converted; + } + else + size += converted; + } + } + if (result != NULL) { + *bytes = 0; + break; + } + + size += 1; /* nul byte at the end */ + result = PyMem_Malloc(size); + if (result == NULL) + return NULL; + bytes = result; + } + return result; +} + +/* In principle, this should use HAVE__WSTAT, and _wstat + should be detected by autoconf. However, no current + POSIX system provides that function, so testing for + it is pointless. + Not sure whether the MS_WINDOWS guards are necessary: + perhaps for cygwin/mingw builds? +*/ +#if defined(HAVE_STAT) && !defined(MS_WINDOWS) + +/* Get file status. Encode the path to the locale encoding. */ + +int +_Py_wstat(const wchar_t* path, struct stat *buf) +{ + int err; + char *fname; + fname = _Py_wchar2char(path, NULL); + if (fname == NULL) { + errno = EINVAL; + return -1; + } + err = stat(fname, buf); + PyMem_Free(fname); + return err; +} +#endif + +/* Call _wstat() on Windows, or encode the path to the filesystem encoding and + call stat() otherwise. Only fill st_mode attribute on Windows. + + Return 0 on success, -1 on _wstat() / stat() error or (if PyErr_Occurred()) + unicode error. */ + +int +_Py_stat(PyObject *path, struct stat *statbuf) +{ +#ifdef MS_WINDOWS + int err; + struct _stat wstatbuf; + + err = _wstat(PyUnicode_AS_UNICODE(path), &wstatbuf); + if (!err) + statbuf->st_mode = wstatbuf.st_mode; + return err; +#else + int ret; + PyObject *bytes = PyUnicode_EncodeFSDefault(path); + if (bytes == NULL) + return -1; + ret = stat(PyBytes_AS_STRING(bytes), statbuf); + Py_DECREF(bytes); + return ret; +#endif +} + +/* Open a file. Use _wfopen() on Windows, encode the path to the locale + encoding and use fopen() otherwise. */ + +FILE * +_Py_wfopen(const wchar_t *path, const wchar_t *mode) +{ +#ifndef MS_WINDOWS + FILE *f; + char *cpath; + char cmode[10]; + size_t r; + r = wcstombs(cmode, mode, 10); + if (r == (size_t)-1 || r >= 10) { + errno = EINVAL; + return NULL; + } + cpath = _Py_wchar2char(path, NULL); + if (cpath == NULL) + return NULL; + f = fopen(cpath, cmode); + PyMem_Free(cpath); + return f; +#else + return _wfopen(path, mode); +#endif +} + +/* Call _wfopen() on Windows, or encode the path to the filesystem encoding and + call fopen() otherwise. + + Return the new file object on success, or NULL if the file cannot be open or + (if PyErr_Occurred()) on unicode error */ + +FILE* +_Py_fopen(PyObject *path, const char *mode) +{ +#ifdef MS_WINDOWS + wchar_t wmode[10]; + int usize; + + usize = MultiByteToWideChar(CP_ACP, 0, mode, -1, wmode, sizeof(wmode)); + if (usize == 0) + return NULL; + + return _wfopen(PyUnicode_AS_UNICODE(path), wmode); +#else + FILE *f; + PyObject *bytes = PyUnicode_EncodeFSDefault(path); + if (bytes == NULL) + return NULL; + f = fopen(PyBytes_AS_STRING(bytes), mode); + Py_DECREF(bytes); + return f; +#endif +} + +#ifdef HAVE_READLINK + +/* Read value of symbolic link. Encode the path to the locale encoding, decode + the result from the locale encoding. */ + +int +_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz) +{ + char *cpath; + char cbuf[PATH_MAX]; + wchar_t *wbuf; + int res; + size_t r1; + + cpath = _Py_wchar2char(path, NULL); + if (cpath == NULL) { + errno = EINVAL; + return -1; + } + res = (int)readlink(cpath, cbuf, PATH_MAX); + PyMem_Free(cpath); + if (res == -1) + return -1; + if (res == PATH_MAX) { + errno = EINVAL; + return -1; + } + cbuf[res] = '\0'; /* buf will be null terminated */ + wbuf = _Py_char2wchar(cbuf, &r1); + if (wbuf == NULL) { + errno = EINVAL; + return -1; + } + if (bufsiz <= r1) { + PyMem_Free(wbuf); + errno = EINVAL; + return -1; + } + wcsncpy(buf, wbuf, bufsiz); + PyMem_Free(wbuf); + return (int)r1; +} +#endif + +#ifdef HAVE_REALPATH + +/* Return the canonicalized absolute pathname. Encode path to the locale + encoding, decode the result from the locale encoding. */ + +wchar_t* +_Py_wrealpath(const wchar_t *path, + wchar_t *resolved_path, size_t resolved_path_size) +{ + char *cpath; + char cresolved_path[PATH_MAX]; + wchar_t *wresolved_path; + char *res; + size_t r; + cpath = _Py_wchar2char(path, NULL); + if (cpath == NULL) { + errno = EINVAL; + return NULL; + } + res = realpath(cpath, cresolved_path); + PyMem_Free(cpath); + if (res == NULL) + return NULL; + + wresolved_path = _Py_char2wchar(cresolved_path, &r); + if (wresolved_path == NULL) { + errno = EINVAL; + return NULL; + } + if (resolved_path_size <= r) { + PyMem_Free(wresolved_path); + errno = EINVAL; + return NULL; + } + wcsncpy(resolved_path, wresolved_path, resolved_path_size); + PyMem_Free(wresolved_path); + return resolved_path; +} +#endif + +/* Get the current directory. size is the buffer size in wide characters + including the null character. Decode the path from the locale encoding. */ + +wchar_t* +_Py_wgetcwd(wchar_t *buf, size_t size) +{ +#ifdef MS_WINDOWS + return _wgetcwd(buf, size); +#else + char fname[PATH_MAX]; + wchar_t *wname; + size_t len; + + if (getcwd(fname, PATH_MAX) == NULL) + return NULL; + wname = _Py_char2wchar(fname, &len); + if (wname == NULL) + return NULL; + if (size <= len) { + PyMem_Free(wname); + return NULL; + } + wcsncpy(buf, wname, size); + PyMem_Free(wname); + return buf; +#endif +} + +#endif |